1. Field of the Invention
The present application generally relates to a motorcycle and a vehicle body cooling structure for a motorcycle that redirects into a space between an engine and a fuel tank airflow created during forward movement of the vehicle.
2. Description of the Related Art
Motorcycles can feature a cowling that covers the front part of the vehicle body. Some of these cowlings include a ventilating structure that directs airflow created during movement of the motorcycle to the inside of the cowling. The ventilating structure directs the airflow between the engine and the fuel tank and other components inside the cowling. The airflow sweeps the air heated by the engine out of the region of the fuel tank. Thus, the fuel tank is less likely to be heated by the engine and an associated radiator.
A conventional motorcycle body cooling structure is disclosed in Japanese Patent No. 2,694,905 (pp. 2-3, FIG. 1), for example. In this arrangement, a structure introduces airflow produced by movement of the motorcycle through an air introduction opening formed at the front end of a cowling. Inside the cowling, the airflow is directed into a space between an engine and a fuel tank. The relatively low-temperature airflow is directed to a location below the bottom of the fuel tank or its vicinity. The airflow is discharged from within the cowling to the rear together with air warmed by a radiator and the engine.
In such constructions, however, the airflow is created by forward movement of the vehicle and a slow moving vehicle will not generate sufficient airflow to adequately reduce the impact of engine heat on the fuel tank. In other words, there is a possibility that the lower surface of the fuel tank will be warmed when the amount of the airflow is decreased when the vehicle is running at a low speed. In some configurations, a heat insulator has been attached to the lower surface of the fuel tank. The heat insulator can reduce the transmission of engine-generated heat to the fuel tank. If, however, the motorcycle is operated at low speeds for a sufficient period of time, then the entire lower part of the fuel tank, including the heat insulator, still may be heated.
In addition, relatively high-temperature air in the engine region sometimes rises due to a negative pressure region created behind a wind screen during normal operating speeds, especially at highway speeds. Accordingly, it is possible that the relatively high-temperature air will increase the temperature of the lower surface of the fuel tank.